Answer
$(A)$
Work Step by Step
The major axis is along the x-axis, center is at (0,0).
The denominator under $x^{2}$ is going to be larger.
The vertices are $(\pm 2,0),\quad a=2, \quad a^{2}=4$
The minor axis has length $2b=2, $
so $\quad b=1, \quad b^{2}=1$
The equation is$\quad$ $\displaystyle \frac{x^{2}}{4}+\frac{y^{2}}{1}=1$,
choice $(A)$